Is it 'legal' to rebroadcast Shoutcast streams in an App ( let's use Apple/iOS as an example ) ..and then sell it?

Is it legal for that matter to rebroadcast streams from any publicly available URL without permission? Perhaps 'rebroadcast' is not even the correct term for this ..

Looking at Apple's App Store.. there are no shortage of streaming Apps that each have hundreds if not thousands of internet radio streams available. I would assume the largest ones ( TuneIn, iHeartRadio, etc ) .. have some sort of blanket permissions that allow them to stream so many stations legally.